Genetic basis of psoriasis vulgaris and its pharmacogenetic potential

TNF-α Gene Promoter -238G>A and -308G>A Polymorphisms Alter Risk of Psoriasis Vulgaris: A Meta-Analysis

Tumor necrosis factor-alpha (TNF-alpha) is a major proinflammatory cytokine and involved in the etiology of psoriasis. The -238G>A and -308G>A polymorphisms influence the transcription of the TNF-alpha gene and have been implicated in psoriasis risk. However, the results from the published studies on the association between TNF-alpha polymorphisms and psoriasis risk are conflicting. Our meta-analysis of a total of 997 psoriasis cases and 943 control subjects from eight published case-control studies for the -238G>A polymorphism and of 1,156 psoriasis cases and 1,083 control subjects from 10 published case-control studies for the -308G>A polymorphism showed that a significantly increased risk was associated with the variant GA+AA genotypes of -238G>A, compared with the GG genotype (odds ratio (OR) 2.60, 95% confidence interval (95% CI) 1.48-4.56), whereas a significantly reduced psoriasis risk was associated with the variant GA+AA genotypes of the -308G>A compared with the GG genotype (OR 0.57, 95% CI 0.45-0.71). Our findings suggest that TNF-alpha -238G>A and -308G>A polymorphisms might be used as biomarkers for psoriasis risk prediction. A single larger study with thousands of subjects and biochemical and biological characterization is warranted to evaluate further the role of -238G>A and -308G>A polymorphisms and psoriasis risk in a population of various ethnicities.

Identification of Susceptibility Loci for Skin Disease in a Murine Psoriasis Model

Psoriasis is a frequently occurring inflammatory skin disease characterized by thickened erythematous skin that is covered with silvery scales. It is a complex genetic disease with both heritable and environmental factors contributing to onset and severity. The CD18 hypomorphic PL/J mouse reveals reduced expression of the common chain of beta(2) integrins (CD11/CD18) and spontaneously develops a skin disease that closely resembles human psoriasis. In contrast, CD18 hypomorphic C57BL/6J mice do not demonstrate this phenotype. In this study, we have performed a genome-wide scan to identify loci involved in psoriasiform dermatitis under the condition of low CD18 expression. Backcross analysis of a segregating cross between susceptible CD18 hypomorphic PL/J mice and the resistant CD18 hypomorphic C57BL/6J strain was performed. A genome-wide linkage analysis of 94 phenotypically extreme mice of the backcross was undertaken. Thereafter, a complementary analysis of the regions of interest from the genome-wide screen was done using higher marker density and further mice. We found two loci on chromosome 10 that were significantly linked to the disease and interacted in an additive fashion in its development. In addition, a locus on chromosome 6 that promoted earlier onset of the disease was identified in the most severely affected mice. For the first time, we have identified genetic regions associated with psoriasis in a mouse model resembling human psoriasis. The identification of gene regions associated with psoriasis in this mouse model might contribute to the understanding of genetic causes of psoriasis in patients and pathological mechanisms involved in development of disease.

CTLA-4 gene polymorphisms and natural soluble CTLA-4 protein in psoriasis vulgaris

CTLA-4 molecule is an important inhibitor of T-lymphocyte activation. Several single nucleotide polymorphisms (SNPs) in the CTLA-4 gene were found, and their associations with many human diseases were described. So far, however, such studies have not been performed in psoriasis vulgaris in Caucasoids. Therefore, we examined the distribution of three CTLA-4 SNPs: -1147C/T, -318C/T and +49 A/G in 116 patients with psoriasis vulgaris and 123 healthy blood donors using the polymerase chain reaction-restriction fragment length polymorphism method. For all three SNPs, the frequencies of alleles, genotypes and three-point haplotypes were very similar in patients and controls, suggesting no contribution of these genetic variants to psoriasis.

The psychosocial burden of psoriasis

BACKGROUND

Skin diseases such as psoriasis can profoundly influence a patient's self-image, self-esteem, and sense of well-being. Psoriasis is a multifactorial inflammatory condition with a disease burden that extends beyond the physical symptoms experienced by patients. Psoriasis affects all aspects of quality of life, including physical, psychologic, social, sexual, and occupational elements.

OBJECTIVE

The goal of this article was to review the published literature on the impact of psoriasis on quality of life.

METHODS

Relevant studies were identified through a comprehensive search of MEDLINE, EMBASE, and the Derwent Drug File databases of English-language articles published between 1993 and 2005 using the terms psoriasis in combination with quality of life, cost, cost-benefit analysis, economic, employment, days lost, healthcare, hospitalization, managed care, outcomes research, occupation, payers, and psychosocial. The reference lists of identified articles were checked for additional studies that might have been missed in the original searches.

RESULTS

Data suggest that social stigmatization, high stress levels, physical limitations, depression, employment problems and other psychosocial co-morbidities experienced by patients with psoriasis are not always proportional to, or predicted by, other measurements of disease severity such as body surface area involvement or plaque severity.

CONCLUSION

It is essential to include measures of psychosocial morbidity when assessing psoriasis severity and treatment efficacy because of the substantial role that psychosocial burden plays in patient perception of disease severity, quality of life, and disease course.